Manufacture of rosin and rosin size of decreased latent foaming tendency



United States Patent MANUFACTURE OF ROSIN AND ROSIN SIZE OF DECREASEDLATENT FOAMING TENDENCY Lucius H. Wilson and William C. Hopkins,Valdosta, 'Ga., and Stanley F. Stafiej, Stamford, Conn., assignors toAmerican Cyanamid Company, New York, N.Y., a corporation of Maine NoDrawing. Application March 7, 1957 Serial No. 644,450

8 Claims. (Cl. 260-97) The manufacture of sized paper on a commercialscale.

is generally performed by beating wood or other cellulosic fibers inaqueous suspension until the fibers have become well hydrated, sizingthe fibers by adding rosin size and alum to the fibrous suspension, anddischarging the suspension upon a movingwire of a- Fourdrinier ma: chineto form a web which becomes paper when subsequently dried andcalendered. In the process the aqueous fibrous suspension is unavoidablysujected to continuous vigorous agitation and aeration throughout its Itconsequently normally tends journey to the wire. to develop foam.

The success of the paper-making process depends upon the laying down ofsuspended fibers in uniform fashion on the Fourdrinier wire so that theweb is continuous and homogeneous. Satisfactory paper is not formed.

when the fibrous suspension contains foam as it is delivered to the wireas the foam causes the fibers to form into bunches, so that it is laidin discontinuous fashion. In such event the wet Web and the resulting2,909,514 Patented 20,

' ICC 2 temperature where significant darkening, decarboxylation orother degradation occurs. In certain instances the acid number of therosin has been observed to increase during the treatment, perhaps as aresult of volatilization of the foam-producing components. (2) Smallamounts of preferred boron compounds are effective, but excess amountsthereof are tolerated without harm. The temperature range andreactiontime being broad, the invention does not depend on the ob.- servance ofnarrowly critical limitations.

(3) The treatment does not introduce any limitation into the utility ofthe rosin. The treated rosin may thus be fortified according toprocedures heretofore known (e.g., by reaction with saligenin, maleicanhydride, paraformaldehyde, etc.) and may be converted into liquid and1 dry size in the same manner as ordinary rosin, i.e., rosin which hasnot been so treated.

' (4) The procedure does not involve the additionlof solvent material tothe rosin, filtration of the rosin, or distillation of the rosin. Itthus does not require the rosin manufacturer .or rosin size manufacturerto vary established procedures.

,More in detail, according to one preferred embodiment of the invention,the rosin to be treated is first .alcohol-freactive oxidic boroncompound is then slowly paper may contain Weak spots or even holes.Paper having pinholes or larger discontinuities is not com- I.

mercially acceptable.

Natural rosin (particularly gum rosin and wood rosin) has pronouncedlatent tendency to foam (i.e., tendency to foam when converted intodilute aqueous sodium rosinate solution and agitated).

We have investigated such rosin in the laboratory to determine the causeof 'its tendency to foam and our evidence is that this foaming is due tothe presence in the rosin of small amounts of organic alcohols. Thepresent invention is principally based upon our discovery that thesealcohols may be rapidly, cheaply, and if desired, substantiallycompletely inactivated by theIchemical action of certain compounds ofboron thereon.

We have found that the latent, foaming tendency of such rosin can bedecreased by heating the rosin in molten form with an oxidic compound ofboron at a temperature between about, 150 C. and 250 C. If desired, therosin may be heated with suflicient of the boron compound and for asufficient time to eifect inactivation of substantially all of thealcoholic foamforming materials present, so that the latent foamingtendency of the resin is substantially completely negatived. Thereafter,the rosin may be converted to liquid rosin size in normal manner bysaponification with aqueous alkali metallalkalisolution. I

The above described process has the folowing principal advantages: V

(1) It does not require the rosin to behated 'to a brought to fluidmolten condition at about 175 C.-200 C. in a closed or open vesselequipped with a stirrer. The

added with vigorous stirring so as to effect a controlled uniformreaction, the temperature being maintained within the range stated. Therosin is maintained at reaction temperature until the reaction iscomplete and any volatile material formed has substantially completelyescaped;

The amount of boron compound which is added in any instance chieflydepends upon the temperature and the duration of the heating, the extentto which it is desired to decrease the latent foaming capacity of therosin,

' and the effectiveness of the particular boron compound as agent forthe purpose. In practice, we prefer to heat the rosin with suflicient ofthe boron compound and for a suflicient time to inactivate between aboutA and of--the--foam-producing components of the rosin. In this range,consumption of the boron compound is minimized while the foaming indexof the rosin is substam tially improved.

- j The invention does not require any temperture higher than 250 C.This temperature is sufliciently high. to convert the foam-producingagents to inactive form, yet is suflicientlylow that the rosin is notdecarboxylated or otherwise harmed. Rosin is sensitive to oxidation,

1 and it is accordingly advantageous to blanket the surface of the rosinduring the treatment with nitrogen or other inert gas. We prefer to usea temperature in excess of about 150 C. as below this temperature thereaction rate is uneconomically slow. 1

The reaction proceeds satisfactorily at atmospheric pressure but wherevolatile organic products .form, the; reaction is often accelerated bydiminished pressure. Very low pressures, however, cause rosin to boiland distill in the range 225 C.250 C. If such low pres; sures areemployed, the temperature of the rosin should be decreased so as tomaintain the rosin below its boiling point, ,as according to theinvention the rosin is not distilled.

Theboron compounds which may be used in the process of the presentinvention include the boron acids,

the boron oxides and the higher organic substituted boron acids andoxides. Thus there may be employed monosodium orthoborate, monosodiumpyroborate, trioctadec'yl borate-and trioleyl borate, tributyl borates,and I phenylboronic acid. We prefer to employ boric acid and 3boric'anhydride as these compounds are easily handled, readilyavailable, and more effective per unit weight than most of the othercompounds. It will be understood that the boron compound may undergothermal decomposition before reacting, and that treatment of the rosinwith the decomposition product is within the scope of the invention.

The invention does not depend upon the addition of any particular amountof boron compound, the particular heating temperature employed, or theduration of the heating period. As stated, we prefer to add sufficientof the boron compound and to heat for a sufficiently long time at asufficiently high temperature so as to inactivate between one-third andabout three-quarters of the alcoholic foam-producing components present.

7 The optimum amount of the boron compound to be added in any oneinstance may be readily determined by making a series of laboratorytrials as illustrated in the examples below and determining the foamingindex of the rosin product by the standard laboratory methods shown inU.S. Patent No. 2,471,714. When rated according to this test, gum rosingenerally has a foaming index hour thereafter. The foaming index of therosin was then determined, and in certain instances the acid number aswell.

The foaming index of the rosin was determined by the following procedureas described in U.S. Patent No. 2,471,714:

The rosin was converted to a 70% solids, 12% free acid liquid size byreaction with the calculated amount of aqueous sodium hydroxidesolution. The size was then diluted to 5% solids with Water. To 20 cc.of this solution there was added 5 cc. of a 10% solution of papermakersalum, Al (SO .14H O. The mixture was then poured into 180 cc. of waterand agitated for 1 minute in a high-speed laboratory Hamilton-Beachmixer. The dispersion was then poured into a SOO-cc. graduate and thevolume of foam measured. The foaming index, expressed in percent, is theratio of the volume of foam to the volume of the liquid present beforethe test and is found according to the following formula:

Run No.

Rosin Boron Opd. Product Acid Foam Index Name ControL...

(Bu-O-O-fi' 3 05 513 (0112) 3 B(OH)3 5 Butyl metaborate.

to escape during the treatment and in part to convert the v v alcoholsto boron ester or boron complex form. The invention will be furtherdescribed with reference to the examples. These examples illustratespecific embodiments of the invention and are not to be construed aslimitations thereon.

Examples 1-18 The following illustrate the decrease in the foaming indexeffected by treating commercial gum and wood rosins with various oxidiccompounds of boron according to the invention.

In each example, 100 gm. of the particular rosin was heated to thetemperature shown in the table in a glass vessel provided withthermometer and stirrer. The boron compound was slowly added withvigorous stirring and the rosin was maintained at reaction temperaturefor an The results show that on a weight basis boric acid is aparticularly effective compound and that results generally improve asthe reaction temperature is increased. Subsequent trials show that inthe range C.-200 C. the reaction is substantially complete within 15minutes after addition of the boron compound.

Example 2 The following illustrates the manufacture of non-foamingfortified rosin size according to the present invention, and shows thatthe treatment with boron does not affect the utility of the rosin.

To gum rosin at 200 C. was slowly added 1% of boric acid with vigorousstirring. After 15 minutes 5% by weight of maleic anhydride was thenadded as fortifying agent. The maleic anhydride was allowed to react at200 C. for two hours and the 70% solids, 12% free acid liquid rosin sizewhich was tested for foaming, according to the method of Example 1.

The procedure was repeated execept that the rosin was reacted with amaleic anhydride first and the boric acid thereafter. The results are asfollows:

Sequence of reaction: Foaming index Boric acid first, then maleic anh. 7Male'ic anh. first, then boric acid 10 The results show that it isadvantageous to postpone admission of the fortifying agent until theboron compound has reacted.

We claim:

1. A method of treating a rosin having a latent foaming tendency becauseof the presence therein of organic alcohols, which comprises heatingsaid rosin in molten form with an alcohol-reactive oxidic compound ofboron at a temperature below the boiling point of said rosin and between150 C. and 250 C.

2. A process according to claim 1 wherein the rosin is gum rosin.

3. A process according to claim 1 wherein the boron compound is boricacid.

4. A process according to claim 1 wherein the rosin is heated withsufiicient of the boron compound and for a sufiicient time to combinewith between about one-third and three-quarters of said organicalcohols.

5. A process according to claim 1 wherein the temperature is between 175C. and 200 C.

6. A method of manufacturing liquid rosin size from 20 2,776,275

a rosin having a latent foaming tendency because of the presence thereinof organic alcohols, which comprises heating said rosin in molten formwith an alcohol-reactive oxidic compound of boron at a temperaturebetween about 150 C. and 250 C. and then saponifying the thus treatedrosin with aqueous alkali metal alkali solution to form liquid rosinsize.

7. A process according to claim 6 wherein the rosin, subsequent toheating with said boron compound and prior to said saponifying, isreacted with a fortifying agent.

8. A process according to claim 7 wherein the fortifying agent is maleicanhydride.

References Cited in the file of this patent UNITED STATES PATENTSBorglin May 1, 1945 Rice Sept. 7, 1948 Strazdins Jan. 1, 1957

1. A METHOD OF TREATING A ROSIN HAVING A LATENT FOAM ING TENDENCYBECAUSE OF THE PRESENCE THEREIN OF ORGANIC ALCOHOLS, WHICH COMPRISESHEATING SAID ROSIN IN MOLTEN FORM WITH AN ALCOHOL-REACTIVE OXIDICCOMPOUND OF BORON AT A TEMPERATURE BELOW THE BOILING POINT OF SAID ROSINAND BETWEEN 150*C. AND 250*C.